The invention relates generally to printers for use with donor and receiver mediums such dye transfer printers, and in particular to a mode of medium-handling in the printer.
A typical dye transfer or dye donor web that is used in a dye transfer printer such as a thermal printer includes a repeating series of three different primary color sections or patches such as a yellow color section, a magenta color section and a cyan color section.
To make a color image print, the respective color dyes (or inks) in a single series of yellow, magenta and cyan color sections on a donor web must be successively heat-transferred imagewise by a print head onto a dye receiver such as paper or transparency sheet or roll. This is generally done according to the following steps (when the dye receiver is a single sheet).
1. The dye donor web and the dye receiver are advanced forward in unison, with a yellow color section of the donor web moving in contact with the dye receiver longitudinally over a bead of selectively heated resistive elements on the print head in order to effect a line-by-line yellow dye transfer imagewise from the yellow color section to the dye receiver. A donor take-up spool draws the dye donor web forward over the print head, and a pair of pinch and drive rollers draw the dye receiver forward over the print head. A platen roller holds the dye receiver in a dye receiving relation with the dye donor web at the print head.
2. Once the yellow dye transfer is completed, the platen roller is retracted from adjacent the print head to allow the pair of pinch and drive rollers to return the dye receiver rearward in preparation for a second pass over the print head.
3. Then, the platen roller is returned to adjacent the print head, and the donor web and the dye receiver are advanced forward in unison, with a magenta color section of the donor web moving in contact with the dye receiver longitudinally over the print head in order to effect a line-by-line magenta dye transfer imagewise from the magenta color section to the dye receiver. The magenta dye transfer to the dye receiver is in exactly the same area on the dye receiver as was subjected to the yellow dye transfer.
4. Once the magenta dye transfer is completed, the platen roller is retracted from adjacent the print head to allow the pair of pinch and drive rollers to return the dye receiver rearward in preparation for a third pass over the print head.
5. Then, the platen roller is returned to adjacent the print head, and the donor web and the dye receiver are advanced forward in unison, with a cyan color section of the donor web moving in contact with the dye receiver longitudinally over the print head in order to effect a line-by-line cyan dye transfer imagewise from the magenta color section to the dye receiver. The cyan dye transfer to the dye receiver is in exactly the same area on the dye receiver as was subjected to the yellow and magenta dye transfers.
6. Once the cyan dye transfer is completed, the platen roller is retracted from adjacent the print head to allow the dye receiver to be returned rearward in preparation for exiting the printer.
7. Then, the pair of pinch and drive rollers advance the dye receiver forward to an exit tray.
Prior art U.S. Pat. No. 5,718,523 issued Feb. 17, 1998 discloses a dye transfer printer in which a platen roller, a pair of entrance pinch and drive rollers, and a pair of exit pinch and drive rollers are mounted on a pivotable support that pivots about an axis of the exit drive roller. When the support is pivoted in one direction, the platen roller is pivoted towards the print head to hold the dye receiver in the dye receiving relation with the donor web, and the entrance pitch and drive rollers and the exit pinch roller are pivoted to similarly change their identical feeding angle at which the dye receiver is successively fed from between the entrance and exit pinch and drive rollers. When the support is pivoted in a reverse direction, the platen roller is pivoted away from the print head to release the dye receiver from the dye receiving relation with the donor web and the entrance pitch and drive rollers and the exit pinch roller are pivoted to change their identical feeding angle back to the original one.
A printer comprising a print head for printing from a donor medium to a receiver medium, a platen member for holding the donor medium in a printing relation with the receiver medium at said print head, a pair of steering and drive rollers for feeding the receiver medium from between the steering and drive rollers, and a movable support for the platen member and the steering roller that moves the platen member towards the print head to hold the receiver medium in the printing relation with the donor medium and away from the print head to release the receiver medium from the printing relation with the donor medium and that moves the steering roller to vary a feeding angle at which the receiver medium is fed from between the steering and driver rollers, is characterized in that:
the support is movable to three positions, a print position in which the platen member is moved towards the print head to hold the receiver medium in the printing relation with the donor medium and the steering roller is moved to change the feeding angle to one for advancing the receiver medium, a feed-only position in which the platen member is moved away from the print head to release the receiver medium from the printing relation with the donor medium and the steering roller is moved to change the feeding angle to one for returning the receiver medium, and an exit position in which the platen member is moved away from the print head farther than in the feed-only position and the steering roller is moved to change the feeding angle to one for exiting the receiver medium.